Golf balls are of two types, these types being one-piece balls and multicomponent balls. A one-piece ball consists of a polymeric sphere into which is molded a plurality of dimples to aid the flight characteristic of the ball. A multicomponent ball consists of a wound or solid core which is covered with a separate and distinct cover. This invention is concerned primarily with the latter-mentioned multicomponent-type golf balls and a means for enhancing the color of the covers in question, however, the invention also can be used with the one-piece balls described above.
For decades, golf ball covers consisted principally of naturally occurring balata. In the last thirty years, synthetic polymeric materials and mixtures thereof have come into widespread use as golf ball covers. In their natural form, neither the natural balata nor synthetic polymeric materials are white in appearance. Thus, in order to impart a white color to the golf balls, a two-part whitening system originally was used. This system involved both the incorporation of a white pigment into the cover material, and the application of a layer of white paint on the outer surface of the cover.
The necessity for applying a layer of white paint to the surface of a golf ball cover was later eliminated by the incorporation of optical brighteners into one or more of the outer layers of the ball, including the cover, a primer layer applied to the cover, and a clear top coat applied as the outermost layer of the ball. The incorporation of optical brighteners into the cover of a golf ball is described in U.S. Pat. No. 4,679,795, the contents of which are incorporated herein by reference. U.S. Pat. No. 4,865,326 describes the use of optical brighteners in a "clear coat" placed on the outer surface of a golf ball. U.S. Pat. No. 5,000.458 describes the inclusion of optical brighteners in a primer coat of a golf ball, the primer being applied between the cover and clear coat to promote adhesion of the clear coat to the golf ball cover.